package com.hao.netty.chapter02.nio;

import com.sun.org.apache.xerces.internal.util.DOMEntityResolverWrapper;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Date;
import java.util.Iterator;
import java.util.Set;

/**
 * @Description //TODO
 * @Date 2020/1/11
 * @Author songhao
 **/
public class MultiplexerTimeServer implements Runnable{

    private Selector selector;
    private ServerSocketChannel serverSocketChannel;
    private volatile  boolean stop;

    public MultiplexerTimeServer(int port){
        try{
            selector = Selector.open();
            serverSocketChannel = ServerSocketChannel.open();

            serverSocketChannel.configureBlocking(false);
            serverSocketChannel.socket().bind(new InetSocketAddress(port),1024);
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
            System.out.println("The time server is start in port:" + port);
        }catch (Exception e){
            e.printStackTrace();
            System.exit(-1);
        }
    }

    public void stop(){
        this.stop = true;
    }

    @Override
    public void run() {
        while(!stop){
            try{
                //设置超时时间
                selector.select(1000);
                //轮询获取所有的事件
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                Iterator<SelectionKey> it = selectionKeys.iterator();
                SelectionKey key = null;
                while(it.hasNext()){
                    key = it.next();
                    it.remove();
                    try{
                        handleInput(key);
                    }catch (Exception e){
                        if(key != null){
                            key.cancel();
                            if(key.channel() != null){
                                key.channel().close();
                            }
                        }
                    }
                }
            }catch (Throwable e){
                e.printStackTrace();
            }
        }
        if(selector != null){
            try{
                selector.close();
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }

    private void handleInput(SelectionKey key) throws IOException{
        if(key.isValid()){
            //处理新接入的请求消息
            if(key.isAcceptable()){
                ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
                SocketChannel sc = ssc.accept();
                sc.configureBlocking(false);

                sc.register(selector,SelectionKey.OP_READ);
            }

            if(key.isReadable()){
                SocketChannel sc = (SocketChannel)key.channel();
                ByteBuffer readBuffer = ByteBuffer.allocate(1024);
                int readBytes = sc.read(readBuffer);
                if(readBytes > 0){
                    readBuffer.flip();
                    byte[] bytes = new byte[readBuffer.remaining()];
                    readBuffer.get(bytes);
                    String body = new String(bytes,"UTF-8");
                    System.out.println("The time server receive order:" + body);

                    String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body) ? new Date(System.currentTimeMillis()).toString() : "BAD ORDER";
                    //写结果信息
                    doWrite(sc,currentTime);
                }else if(readBytes < 0){
                    System.out.println("客户端已关闭...");
                    //对端链路关闭
                    key.channel();
                    sc.close();
                }else{
                    System.out.println("未读取到内容,0字节");
                }
            }
        }
    }

    /**
     * 进行写数据
     * @param channel
     * @param response
     */
    private void doWrite(SocketChannel channel, String response) throws IOException{
        if(response != null && response.trim().length() > 0){
            byte[] bytes = response.getBytes();
            ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
            writeBuffer.put(bytes);
            writeBuffer.flip();
            channel.write(writeBuffer);
        }
    }
}
